Illumination is provided using many types of light sources and distribution methods. In interior office lighting, illumination is typically provided through a combination of overhead luminaires and task lighting. Existing best practices and governmental standards proscribe a fixed total amount of energy per unit area illuminated for these two lighting types. Overhead lighting is well understood. High-quality, suspended, direct-indirect lighting can meet or exceed these goals in virtually every situation. Task lighting is more complicated and usually not deeply discussed in guidelines or regulations.
In addition, the demographics of American society indicate that the workforce is aging. The eye deteriorates with age and older workers may require as much as twice as much light to perform the same task as a younger worker. Appropriate task lighting can assist these workers and make them more productive, without lighting the entire space to an unnecessarily high level.
Task lamps vary widely in shape, performance, cost, and efficiency leading to a bewildering array of options. Also, the portability of task lamps makes them prone to loss or theft. Lighting designers, architects, and engineers have traditionally been unwilling to depend on task lighting for illumination. Without a method of verifying appropriate task lighting, the overhead lighting must be over-designed to ensure proper light levels.
Under-cabinet lights have also used as task lights to increase desk illumination. These lights are not suited for this application. A typical task, such as a single piece of paper, is fundamentally different in size and shape from a typical cabinet. Under-cabinet lights are either too large to efficiently illuminate a task, or too small to fully illuminate the under-cabinet wall.
Beyond the difficulty of selecting and maintaining task lights, there are fundamental energy concerns. Fluorescent tubes or compact fluorescent bulbs have been the most efficient and cost effective technology for task lighting. These sources are only available in a fixed number of packages, and cannot be subdivided into smaller energy loads. The lowest level of the existing packages is relatively high and this leads to over-illumination of task, and potentially illuminance uniformity issues across the space. More simply, there are both lighting quality and energy efficiency drawings to having a single over-illuminated area in a work space. Mandating a single type of lamp for an entire office may lead to small workstations being over-lit and larger workstations have sections of brightness juxtaposed with darker areas. Due to these issues, task lighting has not gained broad acceptance in the building or lighting communities as a reliable tool for increasing light levels in an office space.
Many alternate technologies exist to light workplaces. In particular, LED technology has improved greatly in the past years and has become viable as a solution for targeted applications in the field of general illumination. The existing LED products in the market are designed as direct replacements for existing products, such as task, accent, or under-cabinet lights. These solutions are typically unsatisfactory due to the high cost of LEDs relative to other light source.